To understand what has happened to the Republican Party under Donald Trump, consider the case of Wisconsin Gov. Scott Walker.

There was a time, not too many years ago, when Walker looked like a plausible, even likely, candidate for the Republican presidential nomination.

Walker, who spent nearly all of his adult life running for and holding office, rose to national prominence after a highly visible showdown with his state's public sector unions. He wrote a book about the experience and toured the country touting his policy record and his state's strong economy in the years after the recession. In many ways, he looked like—or at least played the role of—a serious, governance-focused conservative politician.

In 2015, Walker launched a bid for the GOP presidential nomination, positioning himself as the substantive antithesis to the crude triviality of Donald Trump. But it quickly became clear that the governor wasn't ready for the national stage. He stumbled over questions about building a Canadian border wall (really), ending birthright citizenship, and whether or not he supported federal ethanol subsidies (which he was against until he started campaigning for president). Like many Republican candidates that year, he seemed unsure of how to respond to Trump, who dominated the field from early on.

In September 2015, Walker, facing poor polls and financial strains, exited the race. As he did, he called for other struggling GOP candidates to do the same, so that the party could unite behind "a positive conservative alternative to the current front-runner." It was an explicit shot at Trump, and a warning to others in the GOP that the reality-show star's brand of shallow, resentment-driven culture-war politics could overtake the party at the expense of both conservative ideology and governance.

Today, Trump as president commands the strong support of the vast majority of Republican voters, and, at least in public, the backing of nearly all GOP elected officials. He spends his days tweeting about enemies, real and imagined, and fanning the flames of the culture war in order to energize Republican voters. Among the most frequent topics of the president's tweets are the NFL players who have decided to protest police brutality by taking a knee during the national anthem. In both style and (lack of) substance, the Trump takeover that Walker warned about three years ago has come to pass.

Among those who have fallen in line is Scott Walker, who spent part of yesterday—the first day of the NFL's regular season—tweeting inane pablum about the kneeling players and asking whether Tony Evers, his Democratic opponent in Wisconsin's gubernatorial race, supports the player protests. (Walker and Evers are currently tied in the polls.) Among those tweets was this heart-on-flannel Bitmoji, which resembles a goofy parody of flag-waving GOP patriotism.

And none of this staying in the locker room either. STAND UP. Be honorable. Show respect. It's a simple ask compared to what our service members sacrifice EVERY SINGLE DAY for us. pic.twitter.com/vJG91BnLRb

— Scott Walker (@ScottWalker) September 6, 2018

Walker's policy record since exiting the presidential race (like his record prior to entering it) is rife with shady local deal making in the name of job creation, including a county-led plan to locate a FoxConn facility in the state using state subsidies and the threat of eminent domain. That effort was backed by none other than President Trump.

Walker is no longer a figure of national significance, nor is his political trajectory all that unusual. His tweets are embarrassing, but not in a way that stands out, particularly when compared to Trump himself.

But Walker's evolution from policy-focused governor to figure of pure political pandering illustrates the overall trajectory of the GOP, which has surrendered itself almost entirely to Trump's hostile takeover. Donald Trump's victory over Scott Walker, and the Republican Party, is all but complete.